Undermentioned Patent Document 1 discloses a hose clamp formed by annularly bending a plate spring into an annular shape so that two ends thereof are caused to cross on a circumferential plane. A pair of grip tabs are raised from the ends of the hose clamp respectively. The grip tabs are gripped by a gripping tool so that a diameter of the entire hose clamp is expanded. One of the grip tabs is provided with an arch shaped open groove thereby to be formed into a double-legged shape. The other grip tab is formed into a one-legged shape without opening. A locking claw is formed near a root of the one-legged grip tab so as to protrude radially outward. The two-legged grip tab is formed with a catch capable of locking the locking claw. The locking claw is thus locked by the catch, whereby the hose clamp can be retained in an expanded-diameter state by the locking claw and the catch.